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1.
Adv Clin Exp Med ; 30(4): 441-447, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33913263

RESUMEN

BACKGROUND: As ultrasonography provides objective parameters and values, it is a reliable method of examining the structure and dimensions of the masseter muscle. Although the method is well known, there is no standardization in clinical examination and data analysis yet. OBJECTIVES: The study aimed to measure masseter muscle thickness in designated areas to establish the most repeatable and clinically applicable method of ultrasound examination, and to assess differences in measurements in designated areas for clinical purposes by devising the size-independent parameter. The size-independent parameter may potentially be more clinically applicable than distance records, which are affected by the size of the subject. MATERIAL AND METHODS: An ultrasound examination of 124 masseter muscles was performed. Axial examination in 3 horizontal regions (lower, middle and upper) and coronal examination in 2 vertical regions (proximal and distal) was carried out. Masseter muscle thickness was measured in every designated area when relaxed (muscle at rest (RMT)) and with clenched teeth (contracted muscle (CMT)). A morphological independent functional index of thickness difference (FITD) was calculated. RESULTS: The study revealed very high statistical differences between RMT and CMT (p < 0.0001) in all designated areas but with location variations. Masseter muscle thickness significantly differed depending on the examined area and transducer projection. CONCLUSIONS: The ultrasound study showed that masseter muscle thickness significantly differs depending on the examined area. The authors emphasize the necessity to examine the masseter muscle in specified areas with both coronal and axial projections to achieve objective and repeatable examination. Notable clinical value is assigned to FITD, which is independent from the morphological dimensions of the muscle.


Asunto(s)
Músculo Masetero , Músculo Masetero/diagnóstico por imagen , Estándares de Referencia , Ultrasonografía
2.
Georgian Med News ; (311): 63-67, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33814393

RESUMEN

Excessive tooth wear is currently one of the main problems of oral health. Excessive tooth wear affects both function and aesthetics. Teeth with excessive tooth wear cannot be effectively used for biting and chewing food. Treating excessive tooth wear is complex and time consuming. Studies on increasing the effectiveness of treatment of such patients are relevant. The study involved 60 people with a significant degree of excessive tooth wear and a decrease in the height of the bite. We examined patients using measurements of the electromyographic (EMG) activity of mm.masseter and temporalis. The subjects were divided into two groups - in the first group (30 people), the maxillofacial system was prepared for further prosthetics by wearing a removable dental splint-teethguard, in the second group (30 people) we used both removable splint-teethguards and transcutaneous electrical nerve stimulation (TENS). In both groups, an electromyographic study of mm.masseter and temporalis was performed after 1 week, 1 and 2 months of treatment. In patients with excessive tooth wear and a significant decrease in bite height, our method of preparation for orthopedic treatment contributed to a more rapid normalization of mm.masseter and temporalis functions. The results indicate a pronounced positive effect of the use of removable teeth guard and TENS on the normalization of the bioelectric activity of the masticatory muscles in the preparation of patients for orthopedic treatment of excessive tooth wear.


Asunto(s)
Músculo Temporal , Desgaste de los Dientes , Electromiografía , Humanos , Músculo Masetero , Músculos Masticadores , Desgaste de los Dientes/terapia
3.
Georgian Med News ; (310): 45-48, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33658408

RESUMEN

Aim of the study was to assess electrophysiologic characteristics of masticatory muscles, right and left temporalis and right and left masseter, in nasal and oronasal breathing modes. The study was conducted on the group of 30 female volunteers who were referred to the clinic for orthodontic problems. Conflict of interests was ruled out. The research was carried out within a frame of population-based study. In subjects with nasal breathing electromyographic indicators fall within standardized range. In the group of subjects with oronasal breathing electrical activity of masseter and temporalis muscles is asymmetrical. Asymmetry between sides and unevenness between muscle pairs during normalized muscle activity may result from functionally unstable occlusion. When teeth clench on a cotton roll, dentoalveolar proprioceptive signal is too weak to affect electromyographic indicators offering possibility to obtain data solely on muscle activity during maximal voluntary contraction. Indicators of the degree of mean muscle contractility recorded as a result of standardized maximal voluntary contraction show that, in nasal breathing, muscle activity is homogenous and symmetric in the right and left masseter and temporalis muscles, while, in oronasal breathing, it becomes more dissociated with electrical activity - more pronounced in temporalis muscles. Electrophysiologic activity and, consequently, contractility of both temporalis and masseter muscles are reduced compared to subjects with nasal breathing which must be caused by recruitment of less excitable motor units. Results yielded by the study suggest the significance of the state of neuromuscular balance of the masticatory apparatus in the assessment of orthodontic status and possibility of applying electromyographic indicators to estimate the degree of orthodontic dysfunction and develop individualized treatment plans. Study continues in this respect.


Asunto(s)
Músculos Masticadores , Músculo Temporal , Electromiografía , Femenino , Humanos , Músculo Masetero , Contracción Muscular
4.
J Oral Facial Pain Headache ; 35(1): 7-16, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33730122

RESUMEN

AIMS: To investigate whether localized sensitization of the sternocleidomastoid (SCM) muscle using nerve growth factor (NGF) would affect masseter and anterior temporalis muscle sensitivity and pain profiles. METHODS: A total of 28 healthy participants attended two sessions (T0 and T1). At T0, the maximum voluntary occlusal bite force (MVOBF), as well as pressure pain thresholds (PPT), mechanical sensitivity, and referred pain/sensations for the SCM, masseter, and temporalis muscles, were assessed. Participants also completed the Pain Catastrophizing Scale (PCS), the Pain Vigilance and Awareness Questionnaire (PVAQ), and the Neck Disability Index (NDI). After these assessments, 14 participants received an injection of NGF into the SCM, and 14 received an injection of isotonic saline solution. At T1 (48 hours postinjection), the participants were again submitted to the same evaluations. RESULTS: NGF caused significant mechanical sensitization in the SCM (P < .025), but not in the masseter or temporalis muscles (P > .208). It also caused significant increases in NDI score (P = .004). No statistically significant differences were found for MVOBF, frequency of referred pain/sensations, or questionnaire scores (P > .248). CONCLUSION: These results suggest that 48 hours after localized sensitization of the SCM, the primary response is impairment of neck function, but not jaw function.


Asunto(s)
Músculo Masetero , Factor de Crecimiento Nervioso , Fuerza de la Mordida , Electromiografía , Humanos , Umbral del Dolor , Músculo Temporal
5.
J Oral Facial Pain Headache ; 35(1): 72-76, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33730129

RESUMEN

AIMS: To investigate the effect of masticatory muscle contraction on the pressure pain threshold (PPT) of the lateral pole of the temporomandibular joint (TMJ) in patients with TMJ arthralgia and in asymptomatic individuals. METHODS: A total of 72 individuals divided into two groups (group 1: patients with unilateral TMJ arthralgia [n = 36]; group 2: control group, asymptomatic individuals [n = 36]) were compared. The PPT of the lateral pole of the TMJ with and without concomitant masticatory muscle contraction was determined using a digital algometer in both groups. Paired and independent Student t test were used to compare the data within and between groups, respectively. A 5% significance level was used for all tests. RESULTS: Higher TMJ PPT values with concomitant masticatory muscle contraction were found in both groups (P < .001). The amount of increase in PPT with contracted muscles was not significantly different between groups (P = .341), but the TMJ arthralgia group had significantly lower PPT values than the control group regardless of muscle contraction status (P < .001). CONCLUSION: Concomitant masticatory muscle contraction significantly increased the PPT of the lateral pole of the TMJ in relation to relaxed muscles, regardless of the presence of arthralgia.


Asunto(s)
Síndrome de la Disfunción de Articulación Temporomandibular , Artralgia/etiología , Humanos , Músculo Masetero , Músculos Masticadores , Umbral del Dolor , Articulación Temporomandibular
6.
Stomatologiia (Mosk) ; 100(1): 30-33, 2021.
Artículo en Ruso | MEDLINE | ID: mdl-33528953

RESUMEN

THE AIM OF THE STUDY: Was to investigate the effectiveness of combined treatment with elastic bands and splints in patients with masticatory muscle hypertension. 103 patients (37 men and 66 women) aged from 21 to 65 years were examined. The diagnosis was made based on clinical and instrumental (electromyography) methods. Pain intensity was determined using a visual-analog scale (VAS). Elimination of masticatory muscle hypertension in patients of the first group (51 people) was carried out using only splints while patients of the second group (52 people) had a combined therapy with elastic bands and splints. In the second group of patients reliable reducing of pain intensity was observed by day 14 from the start of therapy (4.54±0.5 points), while in the first group of patients it was discovered only by day 21 (5.08±0.6 points). Reliable changing of the bioelectrical activity of masticatory muscles in the second group of patients was observed by the beginning of second week from the start of preliminary therapy, while in the first group of patients it was discovered only by the third week. Thus, the proposed method of masticatory muscles hypertension treatment using elastic bands and splints has features, favorably distinguish it from the other methods of the therapy, because it provides sparing functioning condition for masticatory muscles.


Asunto(s)
Hipertensión , Férulas (Fijadores) , Adulto , Anciano , Electromiografía , Femenino , Humanos , Hipertensión/terapia , Masculino , Músculo Masetero , Músculos Masticadores , Persona de Mediana Edad , Adulto Joven
8.
Sensors (Basel) ; 21(2)2021 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-33451097

RESUMEN

The aim of this preliminary study was to evaluate the short-term changes of occlusal contacts and muscle activity after orthodontic treatment during the use of a multi-layer clear retainer. Evaluation was done with the T-scan and BioEMG systems. A total of 18 subjects were included, who were evaluated at three time intervals-T0 at debonding, T1 at one month after retainer delivery, and T2 at four months after retainer delivery. The T-scan and electromyography (EMG) data were recorded simultaneously. The T-scan system recorded the occlusion time, disclusion time and force distribution. The EMG waves were quantified by calculating the asymmetry index and activity index. The time variables changed but not significantly. Occlusal force decreased in the anterior dentition and increased in the posterior dentition during T0-T2. There was no clear evidence of a relationship between unbalanced occlusal forces and muscle activity. In most subjects, the temporalis anterior muscle was more dominant than the masseter muscle. From this preliminary computerized study, there were no significant changes in the state of the occlusion or muscle activity during the short-term retention period.


Asunto(s)
Músculo Masetero , Adolescente , Adulto , Fuerza de la Mordida , Electromiografía , Femenino , Humanos , Masculino , Músculo Temporal , Diente , Adulto Joven
9.
BMJ Case Rep ; 14(1)2021 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-33462041

RESUMEN

Masseter hypertrophy (MH) is an uncommon disorder which can cause both aesthetic and functional problems. The most common aetiological factors associated with MH are habit of chewing gum, clenching and/or bruxism. The treatment of MH includes conservative management as well as surgical resection of the enlarged muscle and/or bone. Injection of botulinum toxin type A is a relatively new and minimally invasive method for management of masseter muscle hypertrophy, which offers many advantages over conventional surgical management. This paper reports a case of unilateral MH of unknown origin which was treated with injection of botulinum toxin type A, resulting in satisfactory reduction in the volume of muscle and improvement of facial aesthetics.


Asunto(s)
Toxinas Botulínicas Tipo A/uso terapéutico , Hipertrofia/diagnóstico , Músculo Masetero/anomalías , Fármacos Neuromusculares/uso terapéutico , Femenino , Humanos , Músculo Masetero/efectos de los fármacos , Adulto Joven
10.
J Stroke Cerebrovasc Dis ; 30(4): 105623, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33486342

RESUMEN

In the present report, we discussed the case of a 57-year-old man with unilateral masticatory muscle weakness, nystagmus, skew deviation and facial hypesthesia due to pontine tegmental infarction. Trigeminal motor neuropathy attributed to brain infarction is very rare. Brain magnetic resonance imaging revealed a small dot-like infarction lesion in the pontine tegmentum. Masticatory muscle weakness was confirmed by an electrophysiological study performed on the day after admission in which there was an incomplete interference pattern without spontaneous denervation activity, suggesting that the patient's masseter muscle weakness was caused by an infarction of the trigeminal motor nucleus proper or trigeminal motor nerve fascicles rather than Wallerian degeneration of the trigeminal nerve or the progression of masseter muscle degeneration.


Asunto(s)
Infartos del Tronco Encefálico/complicaciones , Parálisis Facial/etiología , Músculo Masetero/inervación , Debilidad Muscular/etiología , Núcleo Motor del Nervio Trigémino/irrigación sanguínea , Enfermedades del Nervio Trigémino/etiología , Enfermedad Aguda , Infartos del Tronco Encefálico/diagnóstico por imagen , Infartos del Tronco Encefálico/fisiopatología , Parálisis Facial/diagnóstico , Parálisis Facial/fisiopatología , Humanos , Masculino , Masticación , Persona de Mediana Edad , Debilidad Muscular/diagnóstico , Debilidad Muscular/fisiopatología , Enfermedades del Nervio Trigémino/diagnóstico , Enfermedades del Nervio Trigémino/fisiopatología
11.
J Craniomaxillofac Surg ; 49(2): 93-97, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33357968

RESUMEN

The aim of this prospective study was to compare the expression of the Notch receptor family with the biomarker for stimulation of satellite cells (SC), which are responsible for functional adaptation. Tissue samples from the masseter muscle were taken presurgically and 7 months later. Samples from controls came from the extraction of third molars. The expression of Notch 1 to 4 and the satellite cell markers CD34, Pax7, and MyoD1 were investigated. PCR was used for relative quantification of gene expression, which was calculated with the ΔΔCT method. The study involved 38 white patients - 10 prognathic, 18 retrognathic, and 10 orthognathic controls. The median value for Notch 1 was significantly reduced presurgically for prognathic (0.46, SD 0.45) and retrognathic (0.57, SD 0.35) patients compared with the controls. Postsurgically, Notch 2 was significantly upregulated in the prognathic group (0.55, SD 0.28/1.37, SD 0.85). Similarly, there was upregulation of Notch 3 in the prognathic group (0.33, SD 0.42/0.59, SD 1.37) and downregulation in retrognathic patients (0.59, SD 0.79/0.52, SD 0.97). Upregulations for the satellite cell markers CD34 and Pax7 were also found in prognathic patients. The significant upregulation of Notch 1-3 and CD34 in prognathics, but unchanged MyoD expression, signals high stimulation for SC and maintenance of the regeneration cell pool. A lower expression of Notch and SC in retrognathic patients could be responsible for weak functional adaptation.


Asunto(s)
Cirugía Ortognática , Procedimientos Quirúrgicos Ortognáticos , Humanos , Músculo Masetero , Músculo Esquelético , Estudios Prospectivos , Receptores Notch
12.
Dermatol Surg ; 47(1): e5-e9, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-33347002

RESUMEN

BACKGROUND: A wide lower face and a square jaw are considered esthetic problems, particularly in Asia. OBJECTIVE: To investigate the optimal dose of a novel botulinum toxin (prabotulinum toxin A) for treating masseteric hypertrophy. METHODS: Ninety subjects with masseteric hypertrophy were randomly divided into 5 groups and treated with placebo (A, normal saline) or prabotulinum toxin A (B: 24, C: 48, D: 72, and E: 96 units). Photography, ultrasonography, and 3-dimensional imaging were performed before and after injection at baseline and at 4, 8, 12, and 16 weeks after treatment. The participants also rated their satisfaction. RESULTS: Masseter thickness significantly reduced in all groups at 12 weeks, compared with that in the placebo group. A dose-dependent reduction in masseter thickness was observed at the resting and maximal clenching positions. Sonography and 3-dimensional imaging revealed a gradual reduction in masseter thickness and volume, respectively, during the first 12 weeks. Despite being slightly effective, a dose of 24 units might be insufficient for resolving square face problems. Patients in Group E reported discomfort during jaw movement. CONCLUSION: Prabotulinum toxin A could effectively improve lower face contour without major complications, with an optimal dose of 48 to 72 units, followed by reinjection after 12 weeks.


Asunto(s)
Toxinas Botulínicas Tipo A/uso terapéutico , Hipertrofia/tratamiento farmacológico , Músculo Masetero/anomalías , Fármacos Neuromusculares/uso terapéutico , Adulto , Toxinas Botulínicas Tipo A/administración & dosificación , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Estética , Femenino , Humanos , Hipertrofia/diagnóstico por imagen , Inyecciones Intramusculares , Masculino , Músculo Masetero/diagnóstico por imagen , Persona de Mediana Edad , Fármacos Neuromusculares/administración & dosificación , Satisfacción del Paciente , República de Corea
13.
Arch Oral Biol ; 122: 104985, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33340921

RESUMEN

OBJECTIVE: To detect the long-term response to unilateral anterior crossbite (UAC) in masticatory muscles and in molecular biomarkers of peripheral blood leukocytes. DESIGN: Fifty-six six-week-old Sprague-Dawley rats were used. The gene-fold changes in peripheral blood leukocytes were detected by the microarray analysis to compare the rats that received 20-week UAC treatment with age-matched controls (n = 4). Muscle atrophy-related gene Fbxo32 was selected based on the data of the microarray analysis verified by using real-time PCR. The remaining 36 rats were randomly separated in the UAC and control groups at 12 and 20 weeks (n = 12). The protein expression of Fbxo32 and the muscle injury and myogenesis-related markers, αB-crystallin and desmin, were detected in the masseter and lateral pterygoid muscles by western blot assay. RESULTS: In the 20-week UAC group, the masseter muscle weight was lower than that in the age-matched control group, and the expression level of Fbxo32 gene in peripheral blood leukocytes was increased according to the microarray analysis confirmed by real-time PCR detection. The increased protein expression levels of Fbxo32 were detected in the masseter in the 20-week UAC group, and the protein expression levels of desmin and αB-crystallin were decreased at this time point. No similar changes were detected in the lateral pterygoid muscle. CONCLUSIONS: Masseter atrophy is induced by long-term stimulation of UAC. The increased expression of the Fbxo32 gene in peripheral blood leukocytes may be a candidate biological marker of masseter atrophy.


Asunto(s)
Maloclusión/fisiopatología , Músculo Masetero/fisiopatología , Animales , Leucocitos Mononucleares , Proteínas Musculares/metabolismo , Músculos Pterigoideos , Ratas , Ratas Sprague-Dawley , Proteínas Ligasas SKP Cullina F-box/metabolismo
14.
Arch Oral Biol ; 122: 105021, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33348206

RESUMEN

OBJECTIVE: The aim of this study was to analyze the function of the palatal muscles in vivo by real-time wireless electromyography in rats. The effects of palatal wounding were also analyzed. METHODS: Microelectrodes were implanted six rats; in the masseter muscle (two-rats) for comparison, in the unwounded soft palate (two-rats) and the soft palate that received a surgical wound (two-rats). Two weeks after implantation, a wound was made in the soft palate using a 1 mm biopsy-punch. Electromyographic measurements and video-recordings were taken weekly to monitor train-duration and peak-amplitude during eating, grooming and drinking. RESULTS: The train-duration of the masseter muscle during eating was 0.49 ±â€¯0.11 s (rat-1) and 0.56 ±â€¯0.09 s (rat-2), which was higher than during grooming. In the unwounded soft palate the train-duration during eating was 0.63 ±â€¯0.12 s (rat-1) and 0.69 ±â€¯0.069 s (rat-2), which was higher than during grooming and drinking. The peak-amplitude for eating in the normal soft palate before surgery was 0.31 ±â€¯0.001 mV (rat-1) and 0.33 ±â€¯0.02 mV (rat-2). This decreased to 0.23 ±â€¯0.03 mV and 0.25 ±â€¯0.11 mV respectively, after surgery. For drinking the peak-amplitude was 0.30 ±â€¯0.01 mV (rat-1) and 0.39 ±â€¯0.01 mV (rat-2) before surgery, which decreased to 0.23 ±â€¯0.09 mV and 0.20 ±â€¯0.14 mV respectively, after surgery. CONCLUSION: The reduced peak-amplitude suggests impaired soft palate function after wounding. This is the first study into the in vivo function of the soft palate after surgical wounding. This model will contribute to develop strategies to improve soft palate function in patients.


Asunto(s)
Músculos Palatinos/fisiología , Paladar Blando/fisiología , Heridas y Traumatismos/fisiopatología , Animales , Electromiografía , Músculo Masetero/fisiología , Paladar Blando/lesiones , Ratas
15.
J Oral Rehabil ; 48(4): 403-410, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33319400

RESUMEN

BACKGROUND: Masticatory movement occurs complicatedly and bilaterally. Although the tongue plays an important role in mastication, bilateral tongue function during mastication has not been clarified yet. OBJECTIVE: To investigate the effect of food properties on posterior tongue activity and coordination of muscles bilaterally by electromyography (EMG). METHODS: Twenty healthy adults (10 males and 10 females; mean age 28 years; range: 22-33 years) participated in this study. Three test foods, gummy jelly (hard food), sponge cake (soft food requiring crushing), and mashed potatoes (soft food not requiring crushing), were used. Bilateral masseter N-EMG (surface electromyography for measuring the muscle activity of posterior tongue) and submental EMG were carried out while the participants chewed three test foods. The participants were instructed to masticate three test foods only on the right side and only on the left side unilaterally. RESULTS: In the case of gummy jelly, N-EMG activity on the mastication side was significantly larger than that on the non-mastication side (P < .01). Regarding temporal relationship between the masseter and N-EMG activity, in the case of gummy jelly, the percentage of cases where the N-EMG peak was observed during masseter muscle EMG bursts was significantly higher than those for sponge cake and mashed potatoes (P < .01). CONCLUSION: N-EMG activity on the mastication side was significantly larger than that on the non-mastication side in the mastication of hard foods. Tongue showed activity pattern changes and coordinated with the masseter muscle depending on food texture.


Asunto(s)
Músculo Masetero , Masticación , Adulto , Electromiografía , Femenino , Alimentos , Humanos , Masculino , Músculos Masticadores , Músculo Temporal , Lengua , Adulto Joven
16.
J Oral Rehabil ; 48(4): 487-516, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33369753

RESUMEN

Understanding jaw muscle activity changes in temporomandibular disorders (TMD) is crucial to guide clinical management. The nature of these changes is currently unclear. Explore changes in jaw muscle activity in TMD. Electronic databases (PubMed, EMBASE, CINAHL, Scopus, Web of Science, Cochrane) and bibliographies were searched from inception to 9 July 2020 for eligible studies, including grey literature. Case-control and interventional studies reporting time-domain and frequency-domain electromyographic measures of jaw muscle activity in TMD and control groups were included. SIGN checklist for case-control studies was used to evaluate risk of bias. Results were pooled for meta-analysis using random-effects model. Confidence in cumulative evidence was established using American Academy of Neurology guidelines. Forty-five studies were included. Most were rated moderate risk of bias. Activity of four muscles (masseter, temporalis, lateral pterygoid, suprahyoids) was assessed across six domains (resting, clenching, chewing, swallowing, concentrating, resisted mandibular movements), with partial meta-analysis scope. Masseter and temporalis activity were significantly higher at rest (P = .05, P < .0001), but lower during brief maximal clenching (P = .005, P = .04) in TMD vs controls. Insufficient data precluded meta-analysis of remaining outcomes and subgroup analysis. Confidence in cumulative evidence ranged from moderate to very low. Changes in jaw muscle activity exist in TMD, which are both task-specific and muscle-specific. It remains unclear whether jaw muscle activity changes vary between TMD subgroups. Muscle function should be considered in clinical management of TMD. Insufficient subgroup data highlight future direction for research.


Asunto(s)
Músculo Temporal , Trastornos de la Articulación Temporomandibular , Adulto , Electromiografía , Humanos , Músculo Masetero , Músculos
17.
PLoS One ; 15(12): e0243495, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33320876

RESUMEN

The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student's t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.


Asunto(s)
Electromiografía , Músculo Masetero/fisiología , Músculo Temporal/fisiología , Adolescente , Adulto , Brasil , Femenino , Humanos , Pueblos Indígenas , Masculino , Masticación/fisiología , Adulto Joven
18.
J Oral Rehabil ; 47(12): 1521-1529, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32898936

RESUMEN

BACKGROUND: Clinical findings suggest that orthodontic treatment with clear aligners (clear aligner therapy/CAT) may cause masticatory muscle soreness in some patients. OBJECTIVE: This multi-site prospective study investigated tooth pain and masticatory muscle soreness and tenderness in patients undergoing CAT and explored whether psychological traits affected these outcomes. METHODS: Twenty-seven adults (22F, 5M; mean age ± SD=35.3 ± 17.6 years) about to start CAT were recruited at three clinics. During CAT, they reported on 100-mm visual analogue scales their tooth pain, masticatory muscle soreness and stress three times per day over 4 weeks (week 1 = baseline; week 2 = dummy aligner; week 3 = first active aligner; week 4 = second active aligner). Pressure pain thresholds (PPTs) were measured at the masseter and temporalis at baseline and after week 4. Mixed models were used to evaluate the outcome measures over time. RESULTS: Clear aligner therapy caused mild tooth pain, which was greater with the passive than the first and second active aligners (both P < .001). Mild and clinically not relevant masticatory muscle soreness was produced by all aligners (all P < .05), with the first active aligner producing less soreness than the dummy aligner (P < .001). PPTs did not change significantly after 4 weeks. Both tooth pain and masticatory muscle soreness were affected by stress and trait anxiety, whilst muscle soreness was affected also by oral behaviours. CONCLUSIONS: In the short term, CAT produces tooth pain and masticatory muscle soreness of limited significance. Frequent oral behaviours are related to increased masticatory muscle soreness during CAT. The medium- and long-term effects of CAT should be further explored.


Asunto(s)
Mialgia , Aparatos Ortodóncicos Removibles , Adulto , Humanos , Músculo Masetero , Músculos Masticadores , Mialgia/etiología , Umbral del Dolor , Estudios Prospectivos
19.
Clin Ter ; 171(5): e414-e420, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32901785

RESUMEN

OBJECTIVE: Surface Electromyography of masticatory muscles (sEMG) is used as a tool to support diagnosis and treatment of Temporomandibular disorders (TMDs). The study aimed at examining jaw muscles pattern in individuals with temporomandibular joint disc displacement with reduction (TMJ/DDR). This sort of subjects was supposed to have a different muscular pattern compared to the control group. MATERIALS AND METHODS: Sixty-four women with unilateral TMJ/DDR and forty TMD-free women underwent a sEMG assessment of masticatory muscles. Descriptive statistics were performed. Student T-Test assessed differences between the two groups. Statistical significance was set at ρ < 0.05. RESULT: The t-test showed statistically significant results only in BAR and SMI scores (ρ value < 0,0001). The other measurements did not differ between the two groups. BAR index values of all healthy subjects were within the reference range. Almost the entire TMJ/DDR group had BAR index out of reference range and anteriorly placed. CONCLUSION: Women with TMJ/DDR showed an altered recruitment of the jaw muscles, with significant difference between the activity of the couple of temporalis and the one of masseters, compared to the control group. A lower chewing efficiency was found in the DDR group compared to the control one.


Asunto(s)
Electromiografía , Disco de la Articulación Temporomandibular/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Adulto , Electromiografía/métodos , Femenino , Humanos , Músculo Masetero/fisiopatología , Masticación , Músculos Masticadores/fisiopatología , Persona de Mediana Edad , Músculo Temporal/fisiopatología , Trastornos de la Articulación Temporomandibular/diagnóstico
20.
J Oral Facial Pain Headache ; 34(3): 281-290, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32870957

RESUMEN

AIMS: To investigate pain sensitivity in the masseter muscle and index finger in response to acute psychologic stress in healthy participants. METHODS: Fifteen healthy women (23.7 ± 2.3 years) participated in two randomized sessions: in the experimental stress session, the Paced Auditory Serial Addition Task (PASAT) was used to induce acute stress, and in the control session, a control task was performed. Salivary cortisol, perceived stress levels, electrical and pressure pain thresholds (PTs), and pain tolerance levels (PTLs) were measured at baseline and after each task. Mixed-model analysis was used to test for significant interaction effects between time and session. RESULTS: An interaction effect between time and session occurred for perceived stress levels (P < .001); perceived stress was significantly higher after the experimental task than after the control task (P < .01). No interaction effects occurred for salivary cortisol levels, electrical PTs, or pressure PTLs. Although significant interactions did occur for electrical PTL (P < .05) and pressure PT (P < .001), the simple effects test could not identify significant differences between sessions at any time point. CONCLUSION: The PASAT evoked significant levels of perceived stress; however, pain sensitivity to mechanical or electrical stimuli was not significantly altered in response to the stress task, and the salivary cortisol levels were not altered in response to the PASAT. These results must be interpreted with caution, and more studies with larger study samples are needed to increase the clinical relevant understanding of the pain mechanisms and psychologic stress.


Asunto(s)
Hidrocortisona , Umbral del Dolor , Estudios Cruzados , Femenino , Humanos , Músculo Masetero , Proyectos Piloto , Saliva , Estrés Psicológico
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